Dr. Michael Har-Noy of Immunovative Therapies, a biotech
company founded in Israel in 2004, says that a common misconception is that
cancer is a disease of the weakened immune system.
Dr. Michael Har-Noy
explains that when a normal cell becomes a tumor cell, changes occurring in the
expression of surface antigens give rise to tumor associated antigens (TAAs)
that theoretically could be detected by one’s immune system. Ehrlich, in 1909,
first proposed that one’s immune system protected against cancer, a concept
adapted in the 1950s by Lewis Thomas and then later by Sir Macfarlane Burnet,
who proposed that a patient’s immune system had a “surveillance” mechanism for
tracking down and killing precancerous and cancerous cells. The basis of this
hypothesis is that tumors constantly arise in one’s body and that one’s immune
system must recognize and destroy cells that have TAAs on their surface.
This theory goes on to predict that in cases where the
patient’s immune system is suppressed, the surveillance mechanism is then
compromised, and the cancer cells grow out of control and clinical disease
becomes detectable. This is the theory behind the concept that the patient’s
immune system in cancer cases is weak, and that this immune system must be
reinforced to attack the cancer effectively.
Dr. Michael
Har-Noy and Immunovative Theories believe that there is, however much
evidence to the contrary. While a small number of the rarer cancers occur in
immune compromised individuals, most human malignant tumors are found in
patients with intact immune systems. Also, many cancers, especially epithelial
cell tumors, have a significant component of inflammatory cells. This includes
diverse leukocyte infiltrates of macrophages, neutrophils, eosinophils, and
mast cells, frequently in the presence of lymphocytes. Malignant tumors are typically
densely infiltrated with immune cells, which argues against inadequate immune
system recognition of TAAs.
Furthermore, many previous attempts to bolster the normal
immune response enhanced rather than suppressed growth of the cancer. For
example, in mice, a newly induced tumor of both mesenchymal and epithelial
origin grows faster if it precipitates a reaction from the patient’s immune
system. Highly immunogenic cancers left undisturbed in their original hosts
often grow faster than tumors that stimulate little or no immune response.
Therefore, the idea that tumors are “invisible” to the patient’s immune system
and that this immune system needs to be augmented appears to be incorrect.
The problem may be that the patient’s immune response to the
tumor is the wrong kind of response. Dr. Michael Har-Noy and his team
at Immunovative Theories believe that in attempting to boost an immunologic
response that has already failed to protect the patient against cancer, tumor
growth may be enhanced rather than suppressed. This is probably why most
immunologic cancer treatments to date have been ineffective.
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